Vegetable & Floriculture Diagnostics

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Guidelines for Sending Vegetable or Floriculture Specimens:

Please submit vegetable or floriculture samples according to the following guidelines, based on the symptoms present. Keep in mind that symptoms observed above ground may be the result of an issue below ground. When in doubt, it is best to send 2-3 whole plants if possible. Shake roots from soil, place roots in a plastic bag, and secure the bag in place with an elastic, twist tie, or string. Place the entire plant in another plastic bag or wrap in dry newspaper before placing in a box or envelope for shipping.

Please do not send plants that are completely dead. Please do not send soil alone: we do not test soil for fungal or bacterial pathogens.

Leaf Spots and Blights: Include tissue with a range of symptoms and sufficient tissue for diagnostic procedures. Diagnosis of an entire planting from 1-2 leaves is difficult. Do not include entirely dead or dry tissue as it of no diagnostic value. Wrap the specimen in newspaper or place it in a plastic bag, then into the envelope for mailing. Never add water or wet paper towels.

Fruit Rots: Select early stages of disease rather than badly rotted tissue. With large fruit such as a pumpkin, cut the affected area out with a knife and submit. Wrap fruit or fruit sections in newspaper, and put into a plastic bag for mailing. Never add water or wet paper towels.

Stem Cankers: When a canker occurs on a large plant, cut a section of the stem with the symptoms, wrap in newspaper and place in a plastic bag for mailing. If the plants are small (1 foot or less), shake the soil from the roots, wrap in newspaper and put into a plastic bag for mailing.

Wilt, Crown Rot or Root Rot - If the plants are 1 foot or less, include the entire plant. Dig the plant, including a good handful of the root system. Leave the soil on the roots. Place the root/soil ball into a plastic bag and tie off at the crown to prevent soil from spilling out. Wrap in newspaper and put into a plastic bag for mailing. If the plants are large, send a portion of the plant that includes the infected tissue. For wilt diseases, we must have lower stem tissue and roots.

Scorch, Defoliation or Poor Growth - These symptoms can be caused by nutritional or environmental factors as well as root rot or vascular disease. Collect a specimen as for wilt (above). A soil or tissue analysis may also be advisable. See UMass Soil and Plant Nutrient Testing Laboratory.

Nematodes in Vegetable Crops - If root galls are present, the roots may be submitted for analysis. Soil samples can be examined for root knot juveniles and other species of plant pathogenic nematodes. Nematode populations are estimated most accurately with a composite sample. Use a 3/4 to 1 inch diameter soil probe, or something similar, and sample to a depth of four inches throughout the site. This depth is a compromise but represents the population distribution of different species fairly well. If a crop is present in the area of concern, submit a root sample along with the soil sample. Place roots and soil in the same bag.

When plant damage is evident: Collect 15 to 20 subsamples from throughout the affected area and bulk them. For comparison, a composite sample may also be taken from an adjacent, healthy appearing area.

When no damage is evident: An area can be sampled by collecting 30 or 40 samples and combining them as one. Keep notes about where you sampled so you can return at a later date and sample the same general area.

Packaging the sample: The soil (at least 1/2 pint) should be placed in a sealable plastic bag to prevent desiccation. Do NOT add water. If submitting more than one sample, clearly mark the sample number on the outside of the container. Paper tags placed in contact with the soil deteriorate quickly. After collection, refrigerate or ship immediately.

Greenhouse Media may also be tested for soluble salts and pH at the Diagnostic Lab. About one cup of soil is required. Media may be sent in the same box as plant specimens, but should be placed in a separate plastic bag. Plant material cannot be used for this test.